Diabetic Macular Edema: What to Know

Diabetic macular edema (DME) is a complication of diabetic retinopathy. It occurs when fluid builds up in the macula, the center portion of the retina. The retina is the layer of cells at the back of your eye that helps convert light into the images you see.

Diabetes is the leading cause of new blindness in the United States. DME is the most common cause of vision loss in people with diabetes.

Thankfully, there are steps you can take to help prevent diabetic macular edema. If you’re already experiencing diabetic macular edema, there are treatment options that can help alleviate your symptoms.

This article will discuss the symptoms, causes, treatments, and risk factors of diabetic macular edema.

Types of Diabetic Macular Edema

There are two key types of diabetic macular edema:

• Non-central-involved diabetic macular edema (mild)
• Central-involved diabetic macular edema (severe)

Both types are characterized by thickening of the retina that is 1 millimeter in diameter or larger. In non-central-involved diabetic macular edema, the thickening doesn't involve the central subfield zone of the macula. The central subfield is the 1 mm area around the center point of the fovea, a small depression in your macula where your vision is sharpest.

In central-involved diabetic macular edema, the retinal thickening does involve the central subfield of the macula. This often causes progressive vision loss.

Tests for Diabetic Macular Edema

To determine if you have diabetic macular edema, your healthcare provider may use one or more of the following tests:

• Visual acuity test: This is the standard test you typically take at your yearly eye exam. It consists of a chart with letters and numbers that decrease in size as you read from the top down. Your healthcare professional usually asks you to cover one eye and read from the lowest line you can see clearly. The test is done on both eyes.
• The Amsler Grid: With this test, you can wear reading glasses if you typically use them. The grid is placed at the same distance you’d normally place a newspaper or a book when reading. You’ll cover one eye and mark any parts of the grid that aren’t clear. You’ll switch eyes and again mark the chart. 
  
• Dilated eye exam: Your healthcare provider will administer eye drops that will cause your pupils to widen. Then, your healthcare provider will examine the retina to see if there’s fluid buildup around the macula. 
  
• Optical coherence tomography: Using a special light and camera, your healthcare provider will look to see if the retina is thick (and how thick) and if the macula is swollen. 
  
• Fluorescein angiography: To see if there’s any damage to the macula, your healthcare provider will inject dye into your arm. They dye travels through the blood vessels until it reaches your eye. A camera photographs your retina to see if there’s damage or disease related to diabetic macular edema.
  

Symptoms of Diabetic Macular Edema

Vision changes are the primary symptoms of diabetic macular edema. These include blurred or distorted vision near or in the center of your field of vision. Colors may also appear dull or washed out.

Causes of Diabetic Macular Edema

Diabetic macular edema is a complication of diabetes. It evolves over time and is caused by poor blood sugar control. It doesn’t occur on its own. Consistently high blood sugar can damage the small blood vessels in your eye.

Initially, this damage starts as diabetic retinopathy, which can impair your vision. If left untreated, fluid from these damaged blood vessels can leak into the macula. This is what causes diabetic macular edema.

Risk Factors for Diabetic Macular Edema

Anyone with type 1 or type 2 diabetes can get diabetic macular edema.

Several risk factors could lead to diabetic macular edema. These include: 

• Diabetes
• Kidney disease
• Very high blood pressure
• High fat levels in the blood
• Fluid retention
• Pregnancy 
  

Treating Diabetic Macular Edema

Treatments for diabetic macular edema start with treating diabetes itself. However, depending on the type or severity of your diabetic macular edema, you may need additional treatments.

Injectable Anti-VEGF Medications

Anti-VEGF medications work to block new blood vessels from developing. They also stop leakage from abnormal blood vessels that could flood the macula.

These drugs are injected directly into the eye, so you may experience some mild pressure. Your healthcare provider will determine how many injections you’ll need. 

The American Diabetes Association recommends anti–VEGF injections as a first-line treatment for most people with central-involved diabetic macular edema that impairs vision.

Laser Therapy

Using laser light, your healthcare provider will try to close and destroy any blood vessels that are leaking into the macula. Typically pain-free, this procedure can help slow or stop the growth of new blood vessels that may further damage your vision.

Laser therapy can help protect your vision and possibly even improve it some. There’s also the possibility you could have permanent blind spots, however.

Anti-Inflammatory Medications

Corticosteroids can be used to reduce swelling of the blood vessels that leads to increased fluid in the macula. You and your healthcare provider will decide on the best way to administer them.

Corticosteroid eye drops are a non-invasive way to help reduce retinal thickness and improve vision. They can be used long-term.

Corticosteroids may also be administered by injection. Because diabetic macular edema is a chronic or long-term problem, multiple injections are typically required. 

To reduce the number of injections, an implant that contains a sustained-release corticosteroid is another option.

If your eye doesn’t respond to steroids or you experience side effects due to steroids, your healthcare provider may try nonsteroidal anti-inflammatory drugs (NSAIDs). 

Preventing Diabetic Macular Edema

The best prevention for diabetic macular edema is managing your diabetes and following a healthy lifestyle. Maintaining proper blood sugar levels, coupled with keeping your cholesterol and blood pressure in check, is important in preventing diabetic macular edema.

It’s also important to get regular eye exams, including the dilated eye exam. This way your healthcare provider can monitor any changes to your vision and check for possible eye damage.

Summary 

Regardless of type, people with diabetes are at higher risk of developing diabetic macular edema, particularly if they already have diabetic retinopathy. Monitoring your eye health by receiving annual eye exams with dilation is crucial to detecting vision changes or damage to blood vessels that could lead to diabetic macular edema.

If you’re diagnosed with diabetic macular edema, there are treatments to effectively treat the condition and preserve your vision.

A Word From Verywell

The onset of diabetic macular edema doesn’t mean you’ll lose your vision. There are effective therapies to treat and repair damage to the macula and blood vessels in your eye to prevent diabetic macular edema from becoming severe. 

The key to preventing diabetic macular edema is to properly manage your diabetes to avoid consistently high blood sugar levels. Keeping your blood pressure and cholesterol levels in check will also aid in preventing diabetic macular edema.

If you’ve noticed changes in your vision or have concerns regarding diabetic macular edema, speak to your primary healthcare provider. They can assess your condition and determine next steps to prevent or alleviate diabetic macular edema.